535: 5.7.3 Authentication unsuccessful

Anonymous
2020-04-16T10:47:36+00:00

Hello,

I have an issue when using an O365 account and sending emails from an application.

The application has been suitable to use tls/starttls, port 587, ect.

When entering an email account and password, the following message occurs:

"535: 5.7.3 Authentication unsuccessful"

I would like to understand, what are the mininal features of an O365 account so that it can be used from another application.

I have performed different tests, which allow me to indicate that the account is Ok.

Thank you.

Microsoft 365 and Office | Subscription, account, billing | For home | Windows

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  1. Anonymous
    2020-06-01T13:24:12+00:00

    Hi,

    has the user, you are using a mailbox? If YES, please check in the admin center -> aktive users, click the user you are using for authentication, then e-mail (sorry for the german screenshots)

    then E-Mail Apps -> configure e-mail-apps 

    Check if authentificated SMTP is checked.

    Best regards

    Chris

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  2. Anonymous
    2020-06-01T14:29:18+00:00

    Hi Chris,

    I have checked that setting. It is checked for all the accounts I am trying to use.

    Best Regards,

    Vishwas

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  3. Anonymous
    2020-06-02T19:00:30+00:00

    My team is also recieveing this issue, and we also have enabled Authenticated SMTP.

    This was working for us two weeks ago, so I think something was just broken behind the scenes.

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  4. Anonymous
    2020-06-10T09:36:28+00:00

    I have an almost identical problem. 

    Telnet:

    open smtp.office365.com 587

    Output:

    220 LO2P265CA0199.outlook.office365.com Microsoft ESMTP MAIL Service ready at Wed, 10 Jun 2020 09:31:18 +0000

    Telnet:

    EHLO

    Output:

    250-LO2P265CA0199.outlook.office365.com Hello [XX.XX.XX.XX]

    250-SIZE 157286400

    250-PIPELINING

    250-DSN

    250-ENHANCEDSTATUSCODES

    250-STARTTLS

    250-8BITMIME

    250-BINARYMIME

    250-CHUNKING

    250 SMTPUTF8

    Telnet:

    AUTH LOGIN

    Output:

    504 5.7.4 Unrecognized authentication type [LO2P265CA0199.GBRP265.PROD.OUTLOOK.COM]

    When I try from a completely different IP network using a different OS and different email package, I get:

    535 5.7.3 Authentication unsuccessful [LO2P265CA0199.GBRP265.PROD.OUTLOOK.COM]

    UK based if that helps.

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  5. Anonymous
    2020-06-10T10:32:20+00:00

    Hi Everyone,

    I managed to fix the problem, my problem was that in the software the credential information took it from another site, had to make a adjustment in the development. Then it worked.

    I do not have the detail of the O365 configuration, I am not the administrator

    Thank you very much!

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